1. Field
One embodiment of the invention relates to a cooling device that can cool an object, and an electronic device that including the cooling device.
2. Description of the Related Art
Japanese Patent Application KOKAI Publication No. 2002-118388, for example, discloses a cooling device used to cool down circuit parts in the housing of a portable computer. The cooling device includes a base member formed on a sheet metal, a heat pipe mounted on the base member, a fin mounted on the base member, that radiates the heat of the heat pipe, a fan unit that cools down the fin, and a cover member that covers the fan unit from above. The heat pipe is thermally connected to the fin by its one end, and it is also thermally connected to the circuit parts by its mid portion. The base member and cover member together as an integral unit constitute a duct, which forms a flow path of air supplied by the fan unit. The base member has a linear groove section formed by, for example, bending carried out a plurality of times. The heat pipe is provided in the groove section. In this manner, the inner surface of the base member is flushed with the exposing surface of the heat pipe. Further, the fan unit is mounted on the upper side of the heat pipe.
In this cooling device, the heat generated from the circuit parts is propagated to the fin via the base member and heat pipe. On the other hand, the air supplied from the fan unit is guided by the base member to the fin. The heat propagated to the fin is released to the atmosphere by this air flow. With the structure in which the inner surface of the base member and the exposed surface of the heat pipe are flushed with each other, the generation of a turbulent flow can be prevented, and thus the air flow can be smoothed during this process.
In the meantime, Japanese Patent Application KOKAI Publication No. 11-274779 discloses an other example of the cooling device, which will now be described. This cooling device includes a heat pipe and two plates between which the heat pipe is interposed. The plates abut on the electronic parts so as to be able to absorb the heat generated from the electronic parts. For the other sections of the plates, a fan unit is provided to release the heat of the plates to the atmosphere by the fan unit.
However, the cooling device disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2002-118388 requires the bending to be carried out onto the base member a plurality of times, which complicates the manufacturing process. Further, the heat pipe is thermally connected to the circuit parts by its mid portion, and therefore the heat transmitted from the circuit parts is propagated towards both end of the heat pipe. The portion of the heat that is propagated towards the fin is released to the atmosphere outside the housing. However, the portion directed towards the opposite end to the fin is never released to the atmosphere, and therefore it undesirably increases the temperature inside the housing. Further, the fan is mounted on an upper side of the heat pipe. With this arrangement, the thickness of the cooling device is increased, which undesirably blocks the thinning of portable computers.
The cooling device disclosed in Jpn. Pat. Appln. KOKAI Publication No. 11-274779 does not have such a structure that heat transmitted from circuit parts is propagated to the fan via a heat pipe, and therefore the heat conductivity may not be fully exhibited.